Electrical heating element



P. J. SMITH ELECTRI CAL HEATING ELEMENT Filed April 19, 1928 Jan. I4, 1930.

\\\\\\\\f /l j Patented Jan. 14, 193() PATENT FFICE PATRICK J. SMITH, F LACONIA, NEW HAMPSHIRE ELECTRICAL HEATING ELEMENT Application filed April 19,

This invention relates to electrical heating elements for use in the tubes of boilers.

An important object ot the invention is to produce a device of this character which may be readily inserted in the boiler tube and which is so constructed that a series thereof may be employed in a boiler tube, thus enabling a single structure to be adapted for use with tubes of different lengths.

A further object of the invention is to produce a device of this character which may be readily and cheaply manufactured and which will be durable and efficient in service.

These and other objects I attain by the construction shown in the accompanying' drawing, wherein for the purpose ot' illustration is shown a preferred embodiment of my invention and wherein Figure l is a vertical sectional view through 520 one of the sections ot a heating element constructed in accordance with my invention;

Figure 2 is a section on the line 2 2 of Figure l;

Figure 3 is a side elevation partially in 5 section of a second section;

Figure t is a sectional view through a boiler tube showing` heating elements disposed therein.

Referring now more particularly to the :o drawing, the heater is constructed in units oi which there are two types, the outer end unit illustrated in Figure l and the inner unit illustrated in Figure 3. Each unit comprises an outer metallic shell l0 having an interior lining ll of mica. Disposed within the mica lining is an insulating and heat resisting core 12, the exterior of which is grooved, as at 13, for the reception of a coil heating element lll. The core l2 has a pair of longi- 40 tudinal passages l5 within which are disposed wires 16, one of which is connected to each end of the heating element 11i. In the end element illustrated in Figure l, these wires are at one end connected to terminal posts l? and at their opposite ends to one of the elements 18 ot' a plug` connector. In the type shown in Figure 3, the opposite ends of the wires 16 are connected to opposite elements of the plug connector.

5o In the use of the device, the sections are 1928. Serial N0. 271,195.

successively inserted in the tube, the connectors of the sections being matched and connected with one another so that in the assembled relation ot the sections a substantially continuous heating element is produced having a plurality of heating units, the resistance wires oit which are connected in parallel to lead wires extending through the elements. Those elements constructed for a certain diameter ot tube may bc employed in such tubes without regard to the length thereof. The heating elements being in parallel, the resistance to operation is materially reduced.

Since the construction hereinbefore set forth is capable ot a certain range of change and modification without materially departing from the spirit of the invention, I do not limit myself to such specific structure eX- cept as hereinafter claimed.

l claim l. An electrical heating element for use in tubular constructions comprising a casing, insulating means within the casing, a heat resisting core within said insulating means, a pair of terminals on the upper end of said core, a pair of socket members countersunk in the lower portion of said core, said sockets being' connected to said terminals, and a heating element mounted in said core and being connected to said terminals.

2. An electrical heating` element for use in tubular constructions comprising a casing, insulating means lining the casing, a grooved heat resisting core mounted within said lining, terminals upstanding from the core at the upper ends thereof, sockets countersunk in the lower ends ot said core, said sockets being connected to the terminals and being adapted to receive the terminals of a second heating unit, and a heating element mounted in the grooved portion ot said core and connected to said terminals.

3. An electric heating element for use in tubular constructions comprising a plurality of cylindrical casings, insulating means lining the casings, grooved heat resisting cores mounted within said linings, terminals mounted on the upper ends of said cores, sockets connected to said terminals and countersunk in the lower ends ot said cores, said 100 sockets being adapted to receive the terminals of the adjacent heating unit whereby to form a single heating unit, and heating elements mounted on said cores in the grooves thereof and Connected to said terminals.

In testimony whereof I hereunto afX my signature.

PATRICK J. SMITH. 

